Pyrazine derivative perfume compositions

ABSTRACT

A novel and attractive range of perfume compositions is provided consisting essentially of at least one known perfume ingredient and at least one member of a certain group of alkoxyalkylpyrazines. These compositions can be added to lotions, cosmetics, hair preparations, soaps, detergents, household preparations, aerosol preparations and industrial or domestic reodourants.

United States Patent 1 1 Bramwell et al.

[451 May 20, 1975 PYRAZINE DERIVATIVE PERFUME COMPOSITIONS Inventors: Alan Bramwell, Cottenham; John William Kidman Burrell; Peter Ward, both of Ashford; Alfred Hagemann, Folkestone, all of England Assignee: Lever Brothers Company, New

York, NY.

Filed: Feb. 4, 1974 Appl. No.: 439,181

Related U.S. Application Data Continuation-impart of Ser. No. 43,166, June 3, 1970, abandoned.

Foreign Application Priority Data June 10, 1969 United Kingdom 29388/69 U.S. Cl. 252/522; 252/89; 252/367;

260/250 B Int. Cl A6lk 7/00 Field of Search 252/522; 260/250 [56] References Cited UNITED STATES PATENTS 3,328,402 6/1967 Winter 260/250 B 3,630,750 12/1971 Buttery 260/250 B 3,669,908 6/1972 Hall 252/522 3,767,425 10/1973 Parliment et a1 260/250 B OTHER PUBLICATIONS Bramwell et al., Tetrahedron Letters, 37, pp. 3215-6, 1969.

Primary ExaminerVeronica O'Keefe Attorney, Agent, or Firm-Arnold Grant, Esq.

[57] ABSTRACT 1 Claim, No Drawings PYRAZINE DERIVATIVE PERFUME COMPOSITIONS This application is a continuation-in-part of application Ser. No. 43,166 filed June 3, 1970 and now abandoned.

This invention relates to perfume compositions and, in particular, is concerned with perfume compositions containing certain alkoxy-alkylpyrazines.

DESCRIPTION OF PRIOR ART Certain alkoxy-alkylpyrazines are known to occur naturally. Thus Buttery (Chem. and Ind. (1969) p490) has reported the natural occurrence of 2-methoxy-3- isobutyl-pyrazine as the main flavour constituent of green bell peppers. He has also claimed that the addition of a methoxy-methyl-, -ethylor-isopropyL pyrazine increases the potato flavour of a potato salad (J. Food Sci., 1971, 36(3), 3636). Murray (Chem. & Ind., 1970 (27) 897-8) has reported the existence of 2-methoxy-3-sec.butyl-, 2-methoxy-3-isobutyland Z-methoxy-3-isopropylpyrazine in peas.

The isolation of 2-methoxy-3-sec.butylpyrazine from galbanum oil by Bramwell et al. has been reported (Tetrahedron Letters (37), p.32l32l6, 1969). This compound has been described as having an intense odour characteristic not, however, being generally descriptive of the odour of galbanum oil.

The synthesis of alkoxy-alkylpyrazines has been described by Winter (U.S. Pat. No. 3,328,402) and Parliment (FP 2,062,168). These compounds can be added in small quantities to a range of foodstuffs and beverages (particularly coffee) in order to improve the roastnut-like flavour characteristics. Gainer has described the manufacture of 2-butoxy-3-methylpyrazine in J. Org. Chem. 26, p2360-3 (1961 This reference does not describe the odour characteristics of the compounds prepared.

The majority of the above references indicate that the alkoxy-alkylpyrazines either represent the main flavour character of the range of foodstuffs or that they have a highly intense and rather overpowering odour characteristic in pure form. There is no hint or suggestion that the addition of a small percentage of these alkoxy-alkylpyrazines would enable the perfumer to create a novel and attractive range of perfume compositions. Surprisingly, however, it has now been found that the alkoxy-alkylpyrazines defined below are valuable agents for modifying or improving the odour of perfumes and other products in a unique and attractive way giving the olfactory sensation of natural flowers, leaves, herbage or wood. These unusual characteristics are quite different from the properties previously attributed to the alkoxy-alkylpyrazines whose existence has already been reported.

SUMMARY OF THE INVENTION The present invention provides a perfume composition consisting essentially of at least one known perfume ingredient selected from the group consisting of odoriferous aldehydes, odoriferous alcohols, odorifer- Representative examples of the odoriferous aldehydes, alcohols, ketones and esters include phenyl ethyl alcohol, linalool, linalyl acetate, amyl salicylate, methyl ionone and hydroxycitronellal. Many other examples of these perfume ingredients are to be found in any well known textbook such as Arctander: Perfume and Flavour Chemicals.

The alkoxy-alkylpyrazines are conveniently added to a blend of known perfume ingredients as a solution of 1 part in 10 to parts of perfume solvent such as benzyl benzoate or diethyl phthalate. Individual alkoxy-alkylpyrazines or blends of these compounds can be used to create the perfume compositions of the invention. The natural odours of the perfume compositions produced according to the present invention represent considerable improvement over supposedly similar odours previously available to the perfumer.

Perfume compositions containing alkoxyalkylpyrazines of the present invention can be used to impart a pleasant odour to a wide variety of products, such as lotions, cosmetics, hair preparations, soaps, detergents and other surfactants, household preparations, aerosol preparations, industrial and domestic reodorants and the like. The alkoxy-alkylpyrazines are conveniently prepared by a number of synthetic routes. A preferred method contemplates chlorination or bromination in the ring of an alkylpyrazine and treating the resulting halogenated alkylpyrazine with an appropriate alkali metal alkoxide, preferably sodium alkoxide or potassium alkoxide. Alternatively, the halogenated alkylpyrazine can be treated with an alkali-metal hydroxide and an appropriate aliphatic alcohol to give the corresponding alkoxy-alkylpyrazines.

The alkoxy-alkylpyrazines defined in this specification each possess strong, individual, natural odour characteristics of a green, herbaceous or floral type. 2-Methoxy-3-sec.butylpyrazine has a powerful green odour reminiscent of ivy leaves and wild vegation which, surprisingly, even at low levels is extremely persistent. This material can modify the odour of a perfume composition at a level of 1 part in 20,000 parts and even make a noticeable change at this concentration in the odour of a perfume compositions containing up to 1,200 times that amount of a woody odour component such as vetiver oil. Furthermore the addition of 1-2 parts by weight of this pyrazine to 100,000 parts by weight phenyl ethyl alcohol will change the fragrance of this alcohol from a bland rose type to a fragrance suggesting the character of a Turkish Rose Otto. A blend of 510 parts by weight of this pyrazine and 100,000 parts by weight terpineol changes the fragrance of the terpineol to one having a sweet herbal character.

A blend of 5 parts by weight 2-methoxy-3- isobutylpyrazine and 100,000 parts by weight amyl salicylate has a fragrance similar to that of Hawthorn Blossom. Furthermore a blend of 5l0 parts by weight of this pyrazine and 100,000 parts by weight terpineol has a fragrance connotation of distilled lime oil as compared with the lilac note of terpineol.

The addition of 2n-propoxy-6-methylpyrazine to many common ingredients modifies the fragrance thereof to a sweeter and softer character. The addition, for example, of 1 part by weight of this pyrazine to 2,000 parts by weight terpineol gives the terpineol a softer lilac character.

In contrast, the addition of methyl methoxypyrazine to either terpineol or amyl salicylate introduces a repulsive foetid odour quite unsuitable to perfumery.

The invention will now be further described with reference to the following Examples, in which all parts are by weight.

EXAMPLE 1 A sweet floral composition of the acacia type was prepared containing the perfumery ingredients as listed below:

Amyl cinnamic aldehyde Benzyl acetate Ylang oil Petitgrain oil terpeneless Heliotropin Aldehyde C16 (1% solution in phenylethyl alcohol) Methyl anthranilate Cinnamic alcohol Rose base Benzoin gum (50% solution in benzyl benzoate) Benzyl alcohol Phenylethyl alcohol Linalool Hydroxycitronellal Anisaldehyde The addition of 1 part ofa 1% solution of 2-methoxy- 3-isobutylpyrazine in diethyl phthalate gave a natural, fresh, flowery odour having a distinct suggestion of orange blossom which was not present in the original sweet floral composition.

EXAMPLE 2 An exotic floral bouquet was prepared, composed of the perfumery ingredients as listed below:

Amyl salicylatc Methyl anthranilate Jasmine absolute Phenylethyl phenyl acetate Linalool lonone Bergamot oil Styrax resinoid Hydroxycitronellal Ylang oil Rose base Benzoin gum (25% solution in benzyl benzoate) The addition of 0.5 parts of 2-n-propoxy-6- methylpyrazine gave an odour note to this floral bouquet suggesting natural tuberose, which cannot be achieved by any other means.

EXAMPLE 3 A perfume composition was prepared, containing the perfumery ingredients listed below:

Methyl nonyl acetaldehyde (50% dilution) Bergamot oil -Bromostyrene Caryophyllene Cinnamic alcohol Citronellol Coumarin Geranyl acetate N l t-71 F4 9! oooomuioo -Continued Hydroxycitronellal dimethyl acetal lndole 10% lsoeugenol Methyl eugenol Methyl ionone Oakmoss absolute Musk ketone Phenyl acetic acid Vetiver oil Bourbon The addition of 0.5 parts of a 2% solution of 2-methoxy-3-sec.butylpyrazine in diethyl phthalate resulted in a composition having an enhanced woody chypre odour.

EXAMPLE 4 An Eau de Cologne perfume was prepared, containing the ingredients listed below:

Bergamot oil 30.0 Lemon oil 32.0 Orange oil sweet 19.0 Petitgrain bigarade 15.0 Rose otto bulked 1.0 Rosemary bulked 3.0

The addition of 0.2 parts of a 2% solution of 2-methoxy-3-sec.butylpyrazine in diethyl phthalate, together with 0.8 parts of 2-n-propoxy-6-methylpyrazine reduced the Eau de Cologne character of the composition and yielded a soft, apple-like, slightly woody fragrance.

EXAMPLE 5 A floral bouquet was prepared, containing the ingredients listed below:

Bergamot oil Coumarin Heliotropin Hydroxycitronellal Linalo Methyl ionone Musk ketone Para tertiary butyl cyclohexyl acetate Phenyl ethyl dimethyl carbinol Rhodinol Sandalwood Ell.

Vetiver oil Bourbon to about 1% by weight of the perfume ingredients. 

1. A PERFUME COMPOSITION CONSISTING ESSENTIALLY OF AT LEAST ONE KNOWN PERFUME INGREDIENT SELECTED FROM THE GROUP CONSISTING OF ODORIFEROUS ALDEHYDES, ODORIFEROUS ALCOHOLS, ODORIFEROUS KETONES AND ODORIFEROUS ESTERS AND AT LEAST ONE ALKOXYALKYLPYRAZINE SELECTED FROM THE GROUP CONSISTING OF 2METHOXY-3-SEC.BUTYLPYRAZINE, 2-METHOXY-3-ISOBUTYLPYRAZINE AND 2-N-PROPOXY-6-METHYLPYRAZINE IN AN AMOUNT VARYING FROM ABOUT 0.001 TO ABOUT 1% BY WEIGHT OF THE PERFUME INGREDIENTS. 